Rotary drilling apparatus



Feb; 28; 1928.

R. A. LINCOLN ROTARY DRILLING APPARATUS Fil ed 'Aug'. 5. 1926 awe/ nto?R. z 'ncal/z Patented Feb. 28, 1928.

.'UNITED STATES OFFICE.

ROBERT A..LINCOLN, OF TONKAWA, OKLAHOMA, ASSIGNOR OF ONE-HALF TO AMERI-CAN IRON & MACHINE WORKS, INC., OF OKLAHOMA CITY, OKLAHOMA, A CORPORA-TION OF OKLAHOMA.

This invention relates to rotary drilling apparatus and moreparticularly to the man.- ner of constructing the drilling pipe foroperating the drills of rotary drilling apparatus.

An im ortant object of the invention is to provi e in. rotary drillingapparatus a drill pipe permittingcirculation of the fluid in the usualmanner, while at the same time maintainin a predetermined buoyancy,float-ing or ten ing to float the drill pipe, so that the operation ofwithdrawing or inserting the drill pipe is materially facilitatedand'the pressure which is applied to the drill may be more closelyregulated.

The invention relates more specifically to the construction of certainsections of the drill pipe to provide an air space which is constantlymaintained during the operation of the drill and which accordinglyprovides a predetermined buoyancy, tending to support the drill. It willbe obvious that with a structure of this character and by the insertionof a predetermined number of Ion ths of the especially constructed pipe,the weight of the pipe and drill being known and the depth of flu idwithin the hole being likewise known, the degree of pressure applied tothe drill can be accurately determined.

vIn the accompanying drawings, wherein for the purpose of illustration apr ferred embodiment of my invention is disclosed and wherein 2-.-Figure 1 is a vertical sectional view through a well embodying adrilling tube constructed in accordance withmy invention" Figure '2 isaiTenlarged vertical sectional view through one of the buoyantsectionsof the drill tubing;

Figure 3 is a section on the line 3-3 of Figure 2.

Referring now more particularly to the .drawings, the numeral 10indicates-a rotary well drill and 11 the drill pipe thereof. This drillpipe is constructed in a plurality of sections, of which certainsections 12 are ordinary and the remaini sections, indicated at 13, are'constructe in accordance with my invention. Each section 13 consists ofan ordinary section of pipe within which is inserted. a section of pipehaving a'smaller "diameter and indicated at 14. In addition to being ofsmaller diameter, the

ROTARY DRILLING APPARATUS.

Application-filed August 5, 1926. Serial No. 127,319.

pipe 14 is preferably of less length than the outer pipe section. At itsupper end, this smaller pipe section is formed with a funnel.

dicated at 16. At its lower ehd, the smaller pipe is flared, as at 17,so that the perimeter of the largerportion of this flared sectionclosely approaches the inner wall of the outer pipe, except throughspaced extensions or lugs 17*, so that spaces 18 are left therebetween.The walls of the flare are further provided with openings 19. Sectionsof this type, when inserted within a'well, trap air in the chamber 20formed between the inner and outer pipes and this trapped air tends tobuoyantly support the pipe.

It will, of course, be obvious that the flare 17 could be omitted, if*so desired, but if this isdone, the lower end of the pipe 14 beingunsupported would render the construction very fragile, which is, ofcourse, an undesirable feature when the rough handling to which suchpipes are subjected is taken into consideration. The flare 17,therefore, provides a support for maintaining the lower end of the pipe14 in properly spaced relation to the walls of the drill p pe while theopenings 18 and 19 provide a means for preventing collection of fluidwithin the space 20. While fluid 'will enter the space 20 in smallquantities, as the device is lowered into the fluid of the well, itwill, of course, be obvious that when the drill pipe is withdrawn, thefluid will drain therefrom and accordingly will not tend to corrode ordestroy the inner pipe. If desired, the ends of the extensions or lugs17 may be welded or otherwise secured to the pipe.

\ While 'I have above consistently referred to the device as a drillpipe, it Wlll, of course,

in the formation of well casings and the heavy pumping pressures willvery probably wear through along its wall at some point during theoperation. By making the chamber open-ended, the buoyancy is effectedonly by the lost air trapping space and whenthe pipe is withdrawn abovethe level of the water within the well, the section will immediatelydrain out any containedwater, so that'no extra weight need be lifted.

Since the construction hereinbefore set forth is capable of a certainrange of change and modification without materially departing from thespirit of the invention, I do not limit myself to such s ecificstructure except as hereinafter claime I claim 1. A floating drill pipesection comprising inner and outer tubes, the inner tube having anexternal diameter considerably less than the internal diameter of theouter tube whereby a "space is provided-therebetween, the upper end ofthe inner. tube being enlarged to engage the outer tube and securedandsealed thereto, the lower end of the in ner tube being flared andhaving the larger portions thereof extendin in close proximity to theinner face of the, wall of the outer tube, said flared portion of theinner tube being perforated. 2. A floating drill pipe section comprisinginner and outer tubes, the inner tube having an external diameterconsiderably less than the internal diameter of the outer tube whereby aspace is provided therebesignature.

inner tube beouter tube and the lower end tween, the upper end of theing. enlarged to engage the secured and sealed thereto,

of the inner tube being flared and having the larger portions thereofextending in close proximity to the inner face of the wall of the outertube, said larger portions of the lower end of the inner tube havingex-. tensions engaging the wall of the pipe.

lower end of the inner tube having exten- V sions engaging the wall ofthe pipe, said extensions being secured to the pipe.

4:. A floating drill pipe section comprising inner and outer tubes, theinner tube havin thin the internal diameter of the outer tube whereby aspace is provided therebetween, the u per end of theinner tube beingenlarge to engage the outer tube and secured and sealed thereto, thebore of the inner tube being in communication with the space between thetubes at the lower end of such space. I

In testimony whereof I hereunto afiix my ROBERT A. LINCOLN.

an external diameter considerably less

